Method and system for locating fault of complex power line, device, and storage medium

This application claims the priority benefit of China application no. 202210203932.0, filed on Mar. 2, 2022. The entirety of the above-mentioned patent application is hereby incorporated by reference and made a part of this specification.

The present disclosure relates to the technical field of fault locating for AC/DC power transmission and distribution lines of power systems, and more particularly, to a method and a system for locating a fault of a complex power line, a device, and a storage medium.

In a power system, AC/DC transmission and distribution lines are important components, faults of which affect the stability of the system and cause the interruption of the power supply for a user. Manual search for fault points is time-consuming labor, and rapid and accurate fault-locating technology is conducive to the timely repair of fault lines and can avoid the economic loss caused by a power outage while reducing the difficulty of manual inspection. Power system fault-locating technology mainly includes an impedance method and a traveling wave method. The impedance method is easily affected by fault resistance, transformer errors, and power parameters, and its practical application effect is not desirable. The traveling wave method has been widely used in power systems because of its simple mechanism and high accuracy but is defective for its uncertain wave speed in a cable, a loss of traveling wave information that may result in a locating fault, and poor reliability and locating accuracy in a multi-branch complex line.

Now a distributed fault-locating technology has a good prospect of engineering application, and a method, system, and DC transmission line for fault locating have been proposed by Chu Xu et al. of Hunan University, disclosing that fault locating by means of sensors in a fault section and adjacent sensors can eliminate the impact of wave speed. However, this needs to determine the fault section first, and a fault-locating equation thereof is complex; the locating equation at both ends and the fault-locating equation along the line are not consistent, and the traveling wave fault-locating calculation often fails in complex branch lines.

With the progress of the construction of new power systems based on new energy, there has been a large-scale introduction of distributed energy, accompanied by more and more complex AC/DC transmission and distribution lines, with an increasing number of branches; a simple, reliable, accurate and fast fault-locating technology is desirable.

Therefore, how to further improve the accuracy and reliability of traveling wave fault locating in multi-branch complex lines and simplify the locating calculation has become an urgent technical problem to be solved in the industry.

It is a major object of the present disclosure to provide a method and a system for locating a fault of a complex power line, a device, and a storage medium that can solve the technical problem of low accuracy and reliability of traveling wave fault locating in the prior art.

To achieve the above object, a first aspect of the present disclosure provides a method for locating a fault of a complex power line, including: acquiring an arrival moment when a traveling wave head reaches a corresponding monitoring point as collected by several traveling wave head monitoring sensors on the complex power line, wherein the traveling wave head monitoring sensors are arranged on a trunk line and a branch line of the complex power line, and the traveling wave head monitoring sensors correspond to the monitoring points on a one-to-one basis; acquiring coordinates corresponding to all the monitoring points in a target coordinate system corresponding to the complex power line, wherein an origin of coordinates of the target coordinate system is any point on the trunk line, the coordinates include a line location and an arrival moment corresponding to a monitoring point, and the line location includes a location on the trunk line and a location on the branch line; locating a fault by using coordinates of first monitoring points on the trunk line, a traveling wave propagation speed from one to another of the first monitoring points, and a trunk line fault-locating equation, so as to obtain a coordinate of a first fault point on the trunk line; determining whether a second fault point exists on the branch line by using the coordinate of the first fault point and a coordinate of a branch point corresponding to each branch line on the trunk line; locating a fault, if there is a second fault point on the branch line, by using the coordinate of the first fault point, the coordinates of the first monitoring points on the trunk line, coordinates of second monitoring points on the branch line, the traveling wave propagation speed from one to another of the first monitoring points, a traveling wave propagation speed from one to another of the second monitoring points, and a branch line fault-locating equation, so as to obtain a coordinate of the second fault point of the complex power line; and determining a target fault point on the complex power line according to the coordinate of the first fault point and the coordinate of the second fault point.

In a possible implementation, the locating a fault by using coordinates of first monitoring points on the trunk line, a traveling wave propagation speed from one to another of the first monitoring points, and a trunk line fault-locating equation, so as to obtain a coordinate of a first fault point on the trunk line includes: establishing a trunk line fault-locating equation group by using the coordinates of all the first monitoring points, the traveling wave propagation speed from one to another of the first monitoring points, and the trunk line fault-locating equation; determining whether the first fault point exists on the trunk line by using the propagation speed from one to another of the first monitoring points in a solution of the trunk line fault-locating equation group; and determining the coordinate of the first fault point according to the propagation speed from one to another of the first monitoring points if the first fault point exists on the trunk line.

In a possible implementation, the locating a fault by using the coordinate of the first fault point, the coordinates of the first monitoring points on the trunk line, coordinates of second monitoring points on the branch line, the traveling wave propagation speed from one to another of the first monitoring points, a traveling wave propagation speed from one to another of the second monitoring points, and a branch line fault-locating equation, so as to obtain a coordinate of the second fault point of the complex power line includes: establishing a branch line fault-locating equation group by using the coordinate of the first fault point, the coordinates of the first monitoring points on the trunk line, the coordinates of the second monitoring points on the branch line, the traveling wave propagation speed from one to another of the first monitoring points, the traveling wave propagation speed from one to another of the second monitoring points, and the branch line fault-locating equation, so as to determine the coordinate of the second fault point.

In a possible implementation, the trunk line fault-locating equation includes:

In a possible implementation, the branch line fault-locating equation includes:

In a possible implementation, if the arrival moment collected by any of the traveling wave head monitoring sensors is not acquired, the trunk line fault-locating equation includes:

In a possible implementation, the method further includes: arranging at least two traveling wave head monitoring sensors on the trunk line if the traveling wave propagation speed is known; and arranging at least three traveling wave head monitoring sensors on the trunk line if the traveling wave propagation speed is unknown.

To achieve the above object, a second aspect of the present disclosure provides a system for locating a fault of a complex power line, including: a locating host, and traveling wave head monitoring sensors arranged on the complex power line; wherein the locating host includes: a communication module, a data processing module, a locating calculation module, and an output display module; the communication module, the data processing module, the locating calculation module, and the output display module are electrically connected in sequence.

The traveling wave head monitoring sensor is used for monitoring a traveling wave of a voltage or a traveling wave of a current of the complex power line so as to obtain an arrival moment when a traveling wave head reaches each monitoring point, and the traveling wave head monitoring sensors correspond to the monitoring points on a one-to-one basis; the communication module is used for communicating with the traveling wave locating sensor, and acquiring the arrival moment of the traveling wave head and a traveling wave waveform; the data processing module is used for performing data processing on the arrival moment and traveling wave waveform, and outputting the data-processed arrival moment and traveling wave waveform to the locating calculation module; the locating calculation module is used for obtaining a coordinate of each monitoring point by using the arrival moment corresponding to each of the monitoring points and a line location of the monitoring point, and locating a fault by using coordinates of first monitoring points on the trunk line, a traveling wave propagation speed from one to another of the first monitoring points, and a trunk line fault-locating equation, so as to obtain a coordinate of a first fault point on the trunk line; determining whether a second fault point exists on the branch line by using the coordinate of the first fault point and a coordinate of a branch point corresponding to each branch line on the trunk line; locating a fault, if there is a second fault point on the branch line, by using the coordinate of the first fault point, the coordinates of the first monitoring points on the trunk line, coordinates of second monitoring points on the branch line, the traveling wave propagation speed from one to another of the first monitoring points, a traveling wave propagation speed from one to another of the second monitoring points, and a branch line fault-locating equation, so as to obtain a coordinate of the second fault point of the complex power line; and determining a target fault point on the complex power line according to the coordinate of the first fault point and the coordinate of the second fault point; the output display module is used for displaying each monitoring point and the coordinate of each monitoring point on the complex power line, the target fault point and a coordinate of the target fault point, and fault distance information.

To achieve the above object, a third aspect of the invention provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, causes the processor to perform the steps of the first aspect or any possible implementation.

To achieve the above object, a fourth aspect of the invention provides a computer device including a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of the first aspect or any possible implementation.

The embodiments of the present disclosure render the following advantageous effects.

The present disclosure provides a method for locating a fault of a complex power line. With the method, several traveling wave head monitoring sensors are provided on a complex power line, and the traveling wave head monitoring sensors correspond to monitoring points on a one-to-one basis, so as to obtain several monitoring points on the complex power line; the complex power line is transformed into coordinates in conjunction with an arrival moment and a line location corresponding to the monitoring points, thereby establishing a trunk line fault-locating equation related to the line location, the arrival moment, and a traveling wave propagation speed; a first fault point can thus be derived simply and quickly; on the basis of a coordinate of the first fault point and a coordinate of a branch point corresponding to a branch line on the trunk line, a determination is made as to whether it is located on the branch line, and if it is located on the branch line, a branch line fault-locating equation related to the line location, the arrival moment, and the traveling wave propagation speed is established; a second fault point can thus be derived simply and quickly; finally, a target fault point of the complex power line can be obtained on the basis of the first fault point and the second fault point.

In theory, there is no dead zone in locating the fault, and it is not necessary to determine a fault section first; the equation is simple, and so is the locating principle. This method addresses the deficiency in double-ended traveling wave locating where the fault section needs to be determined first and the location accuracy is affected by a fixed light speed of the traveling wave; a locating path needs not to be planned again, and the wave speed can be calculated in real-time, hence the locating calculation is reliable and accurate.

The embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. It is to be understood that the embodiments described are only a few, but not all embodiments of the invention. Based on the embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without inventive effort fall within the scope of the present disclosure.

With reference to, a schematic diagram of a complex power line according to an embodiment of the present disclosure, the complex power line herein is a crisscross power transmission line composed of various line types, such as a busbar, a trunk line, and a branch line. With reference to, the complex power line includes a busbar, a busbar, a trunk line, a branch line, a branch line, and a branch line, wherein traveling wave head monitoring sensorsare provided at head and tail ends of and along the trunk line, and the traveling wave head monitoring sensorsare provided at the tail ends of the branch line, the branch line, and the branch line. A provision location can be selected to be at a connection of cables and overhead lines of different types, a connection of two lines with different line diameters, and a section of a long power line where accurate locating is desirable; it needs to be noted that where and how many of the sensors are arranged can be determined as appropriate. With continued reference to, eight sensorsare provided in, and each of the traveling wave head monitoring sensorsis used for measuring an arrival moment when a wave head reaches a location (namely, a monitoring point) thereof, the arrival moments are respectively denoted as t, t, t, t, t, t, t, and t, which are also the arrival moment when the traveling wave head reaches each monitoring point. It will be appreciated that the power line shown inis by way of example only and is not particularly limiting.

With continued reference to, a flowchart of a method for locating a fault of a complex power line according to an embodiment of the present disclosure is shown. The method shown inincludes the steps below.

In step, an arrival moment when a traveling wave head reaches a corresponding monitoring point is acquired as collected by several traveling wave head monitoring sensors on the complex power line, wherein the traveling wave head monitoring sensors are arranged on a trunk line and a branch line of the complex power line, and the traveling wave head monitoring sensors correspond to the monitoring points on a one-to-one basis.

It should be noted that the traveling wave head monitoring sensor is used for collecting waveform information about a traveling wave, including but not limited to the arrival moment when the traveling wave head reaches the corresponding monitoring point and a waveform of the traveling wave. In this embodiment, the traveling wave head monitoring sensors are separately arranged on the complex power line, that is, it is necessary to arrange the traveling wave head monitoring sensors on a multi-branch complex power line so as to record the moments when the traveling wave head reaches the monitoring points; with continued reference to the example of, a number of the sensors may be eight, and the sensors are respectively arranged on the trunk line, the branch line, and the branch line. It will be appreciated that more monitoring points may be provided for a more complex power line or different fault detection requirements, that is, the number of the sensors may be greater, and the examples here are not intended to be limiting. The fault occurrence moment and the arrival moment when the traveling wave head reaches the traveling wave head sensor are shown in a 24-hour or 12-hour clock, converted into microseconds or nanoseconds.

In step, coordinates corresponding to all the monitoring points in a target coordinate system corresponding to the complex power line are acquired, wherein an origin of coordinates of the target coordinate system is any point on the trunk line, the coordinates include a line location and an arrival moment corresponding to a monitoring point, and the line location includes a location on the trunk line and a location on the branch line.

Furthermore, it is also necessary to acquire the coordinates of all the monitoring points in the target coordinate system corresponding to the complex power line, wherein the coordinates can reflect the line location of each monitoring point in the complex power line; the target coordinate system is established on the basis of the line location and the arrival moment; the origin of coordinates of the target coordinate system is any point on the trunk line; once the origin of the coordinates is determined, the whole power line can be transformed into coordinates along the trunk line; preferably, the origin of coordinates can be the head end of the trunk line; the trunk line takes the monitoring point at the head end of the line as the origin of coordinates, that is, x=0, and lengths from the monitoring points along the line to the head end are L, L, L, . . . , L, respectively, where i is a serial number of all the monitoring points 0, 1, 2, 3, . . . , i, and x=L. As a result, the location on the trunk line of each monitoring point is the corresponding line length, and a coordinate array on a horizontal axis X is (x, x, x, x, . . . , x). Furthermore, the branch line is transformed into coordinates by taking an intersection point of the trunk line and the branch line as a starting point, and deriving coordinate arrays (x, y), (x, y), . . . , (x, y), . . . , (x, y) of the traveling wave head monitoring sensors on the branch line, where j is a j-th branch line, and n is an n-th sensor on the j-th branch line.

By way of example, with reference toand in conjunction with, a method for establishing the target coordinate system is described, whereinis a schematic diagram of the target coordinate system corresponding to the complex power line in an embodiment of the present disclosure; the lengths L, L, L, L, L, Land Lof each traveling wave monitoring sensorof the power line along the trunk lineare obtained, and the coordinate of the point is (x, t) assuming that the sensor at the busbarend is the origin of coordinates, x=0, and tis the moment when a fault traveling wave head reaches the sensor; the coordinate locations of all the line wave head monitoring sensors arranged along the trunk line are (x, t), (x, t), (x, t), and (x, t), where x=L+L, x=L+L+L, x=L+L+L+L, x=L+L+L+L+L+L+L, and t, t, t, and tare the moments when the traveling wave head reaches the sensors, respectively.

Furthermore, the branch line, the branch line, and the branch lineare transformed into coordinates, and the coordinate locations of all the line wave head monitoring sensors arranged on the branch line are denoted as (x, y, t) where x=L+L+L, and y=L+L, (x, y, t) where x=L+L+L+L, and y=L+L, and (x, y, t), where x=L+L+L+L+L+L, and y=L; t, t, and tare the moments when the traveling wave head reaches the sensors, respectively. Through the transformation to coordinates, the target coordinate system corresponding to the complex power line can be obtained. It can be understood that the location on the trunk line is denoted by x and the location on the branch line is denoted by y. Thus, the coordinates of the monitoring points on the trunk line can be (x, y, t), and the coordinates of the monitoring points on the branch line can be (x, y, t), where xis the location on the trunk line of a monitoring point i on the trunk line, tis the arrival moment of the monitoring point i on the trunk line, xis the location on the trunk line of a monitoring point n on a branch line j, yis the location on the branch line of the monitoring point n on the branch line j, tis the arrival moment of the monitoring point n on the branch line j.

In step, a fault is located by using coordinates of first monitoring points on the trunk line, a traveling wave propagation speed from one to another of the first monitoring points, and a trunk line fault-locating equation, so as to obtain a coordinate of a first fault point on the trunk line.

In this embodiment, the fault can be located by using the coordinates (x, t) of the first monitoring points on the trunk line, the traveling wave propagation speed from one to another of all the first monitoring points, and the trunk line fault-locating equation, so as to obtain the coordinate of the first fault point on the trunk line, wherein the fault locating is a process of searching for the first fault point on the trunk line, and can be understood as a process of solving the trunk line fault-locating equation so as to obtain the coordinate of the first fault point. Herein, the trunk line fault-locating equation is established on the basis of the traveling wave propagation relationship among all the monitoring points, for example, an equation related to a displacement and duration of the traveling wave propagation and the traveling wave propagation speed, hence the coordinate of the possible first fault point can be derived from the trunk line fault-locating equation to realize fault locating. It is to be understood that the coordinates of the first monitoring points on the trunk line can be (x, t), and thus the coordinate of the first fault point can be (X t), where the traveling wave propagation speed from one to another of all the first monitoring points can be v.

In step, a determination is made as to whether a second fault point exists on the branch line by using the coordinate of the first fault point and a coordinate of a branch point corresponding to each branch line on the trunk line.

Furthermore, a traveling wave fault on the trunk line included in the complex power line may also be caused by a branch line traveling wave fault, and therefore it is necessary to determine whether there is a fault on the branch line. Specifically, a determination is made as to whether there is a second fault point on the branch line by using the coordinate of the first fault point and the coordinate of the branch point corresponding to each branch line on the trunk line. It can be understood that each branch line branches off from the trunk line, and therefore there is an intersection point for both the branch line and the trunk line, and the intersection point can be referred to as the branch point. For example, a determination is made as to whether the second fault point exists on the branch line by determining whether the line location included in the coordinate of the first fault point is the same as the line location corresponding to the branch point, and if so, the second fault point exists on the branch line; if not, there is no second fault point on the branch line.

Note that if there is no second fault point on the branch line, then a target fault point can be derived from the coordinate of the first fault point. If there is a second fault point on the branch line, the method proceeds to step.

In step, a fault is located, if there is a second fault point on the branch line, by using the coordinate of the first fault point, the coordinates of the first monitoring points on the trunk line, coordinates of second monitoring points on the branch line, the traveling wave propagation speed from one to another of the first monitoring points, a traveling wave propagation speed from one to another of the second monitoring points, and a branch line fault-locating equation, so as to obtain a coordinate of the second fault point of the complex power line.

It can be understood that if there is a second fault point on the branch line, it is necessary to continue to determine the coordinate of the second fault point on the branch line. Specifically, the fault is located by using the coordinate of the first fault point, the coordinates of the first monitoring points on the trunk line, the coordinates of the second monitoring points on the branch line, the traveling wave propagation speed from one to another of the first monitoring points, the traveling wave propagation speed from one to another of the second monitoring points, and the branch line fault-locating equation, so as to obtain the coordinate of the second fault point of the complex power line. Herein, the branch line fault-locating equation is established on a traveling wave propagation relationship among all the monitoring points, for example, an equation related to a displacement and duration of the traveling wave propagation and the traveling wave propagation speed, hence the coordinate of the possible second fault point can be derived from the branch line fault-locating equation to realize fault locating. The coordinate of the second fault point can be (x, y, t), and the coordinates of the second monitoring points can be (x, y, t).

In step, a target fault point on the complex power line is determined according to the coordinate of the first fault point and the coordinate of the second fault point.

The present disclosure provides a method for locating a fault of a complex power line. With the method, several traveling wave head monitoring sensors are provided on a complex power line, and the traveling wave head monitoring sensors correspond to monitoring points on a one-to-one basis, so as to obtain several monitoring points on the complex power line; the complex power line is transformed into coordinates in conjunction with an arrival moment and a line location corresponding to the monitoring points, thereby establishing a trunk line fault-locating equation related to the line location, the arrival moment, and a traveling wave propagation speed; a first fault point can thus be derived simply and quickly; on the basis of a coordinate of the first fault point and a coordinate of a branch point corresponding to a branch line on the trunk line, a determination is made as to whether it is located on the branch line, and if it is located on the branch line, a branch line fault-locating equation related to the line location, the arrival moment, and the traveling wave propagation speed is established; a second fault point can thus be derived simply and quickly; finally, a target fault point of the complex power line can be obtained on the basis of the first fault point and the second fault point.

In theory, there is no dead zone in locating the fault, and it is not necessary to determine a fault section first; the equation is simple, and so is the locating principle. This method addresses the deficiency in double-ended traveling wave locating where the fault section needs to be determined first and the location accuracy is affected by a fixed light speed of the traveling wave; a locating path needs not to be planned again, and the wave speed can be calculated in real-time, hence the locating calculation is reliable and accurate.

With reference to,is another flow diagram of the method for locating a fault of a complex power line according to an embodiment of the present disclosure, and the method as shown inincludes the steps below.

In step, an arrival moment when a traveling wave head reaches a corresponding monitoring point is acquired as collected by several traveling wave head monitoring sensors on the complex power line, wherein the traveling wave head monitoring sensors are arranged on a trunk line and a branch line of the complex power line, and the traveling wave head monitoring sensors correspond to the monitoring points on a one-to-one basis.

In step, coordinates corresponding to all the monitoring points in a target coordinate system corresponding to the complex power line are acquired, wherein an origin of coordinates of the target coordinate system is any point on the trunk line, the coordinates include a line location and an arrival moment corresponding to a monitoring point, and the line location includes a location on the trunk line and a location on the branch line.

It should be noted that stepsandare similar to stepsandshown in, and for brevity, the description will not be repeated here, and specific reference will be made to the description of stepsandabove.

In step, a trunk line fault-locating equation group is established by using the coordinates of all the first monitoring points, the traveling wave propagation speed from one to another of the first monitoring points, and the trunk line fault-locating equation.

In a possible implementation, the location on the trunk line of the fault is x and the fault occurrence moment is t, and a distance of (x−x) is derived to be (t−t)v, hence the trunk line fault-locating equation can be as follows: